The precollisional locations and geometries of the Lhasa terrane (LT) are critical to constrain the India‐Asia collision. However, the inclinations of the Cretaceous paleomagnetic data obtained from the northern limb of folds are obviously lower than those obtained from the southern limb, which cause large discrepant paleolatitudes of the LT prior to India‐Asia collision. Here, we carried out a new paleomagnetic investigation on the Late Cretaceous Jingzhushan Formation red beds in the far western LT. The tilt‐corrected site mean direction yielded a palaeopole at 74.4°N, 226.0°E with A95 = 3.8° (N = 54). This paleomagnetic data set passes fold tests and indicates that the studied area was located at 19.6° ± 3.8°N during the Late Cretaceous. However, the mean inclination calculated from the northern limb of folds (Is = 19.0°) is significantly lower than that of the southern limb of folds (Is = 51.8°). This inclination discrepancy of the Jingzhushan Formation red beds may be attributed to the syntectonic sedimentation. Nevertheless, the site mean direction obtained from both limbs of folds is generally consistent with the site mean direction after syntectonic‐sedimentation correction. Our new paleomagnetic results, combined with the reliable Cretaceous paleomagnetic results from the LT showed that the southern margin of Asia had a present‐day relatively east‐west alignment prior to India‐Asia collision.

To better constrain the origin and drift history of the North Qiangtang terrane (NQT), we report a well‐dated paleomagnetic pole from the Late Permian volcanics of the NQT that appears to average out secular variation. Our new results yield a paleolatitude of −7.6 ± 5.6°N at ~259 Ma for our sampling area, which confirms the NQT drifted northward during the Permian and Triassic periods. The equatorial paleolatitude of the NQT is similar to that of the coeval South China block, demonstrating that they were in close proximity. Combined with palaeontological and magmatic evidence, paleomagnetic constraints on the drift of the NQT in the Permian indicate that the NQT moved northward together with the South China block at this time. The paleolatitude evolution of the NQT implies that the NQT rifted from the northern margin of the Gondwana in the Devonian, which is earlier than the departure time of the South Qiangtang terrane.

The timing of the north-south collision between two terranes can be determined by the overlap of their paleolatitudes or the change of their convergence rate. For example, the overlapping paleolatitudes of the Lhasa terrane and Tethyan Himalaya and the dramatic decrease in the velocity of the Indian plate are usually ascribed to the India-Asia collision at~55 Ma. However, little is known about the paleolatitudinal evolution and velocity change of the Lhasa terrane resulting from the Lhasa-Qiangtang collision during the Jurassic-Cretaceous period. To better constrain the velocity change of the Lhasa terrane during this period, to constrain when and where the Lhasa-Qiangtang collision occurred, and to assess the distribution of land and sea in the Tethyan realm, we provide a high-quality Cretaceous paleomagnetic pole obtained from the limestone from the western part of the Lhasa terrane, which yields a paleolatitude of~16.8°± 1.9°N for the sampling area (32.2°N, 80.8°E) during the time interval of 113-72 Ma. We compile existing paleomagnetic results from the Lhasa terrane, Qiangtang terrane, Tethyan Himalaya, and India and reveal that the Lhasa-Qiangtang collision most likely occurred at or near the J/K boundary at~19°N for the reference point at (32°N, 88°E) and that the Neo-Tethys reached its maximum width (≥~7450 km) during this period.

No abstract

The breakup of eastern Gondwana is among the hottest topics in the Earth sciences because of its effect on global climate during the Jurassic-Cretaceous, its influence on the evolution of life, and its importance to paleogeographic reconstruction. To better constrain the Jurassic and Cretaceous paleogeographic position of the Tethyan Himalaya and the breakup of eastern Gondwana, a combined paleomagnetic and geochronological study was performed on the Zhela and Weimei Formations lava flows, dated at~138-135 Ma, in the Luozha area of the eastern Tethyan Himalaya. Both positive fold and reversal tests together with a maximum grouping at 100% unfolding indicate that the characteristic remanent magnetization directions are primary magnetizations acquired before folding. The tilt-corrected directions yielded a paleopole at 0.9°N, 293.4°E with A 95 = 7.0°and a corresponding paleolatitude of 53.5°S ± 7.0°S for the Luozha sampling area (28.9°N, 91.3°E), validating that the original erupted position of the Zhela and Weimei Formations lava flows was located in the center of the Kerguelen mantle plume. Our new results, together with the published paleomagnetic, geochronological, and geochemical results, demonstrate that the Comei-Bunbury large igneous province originated from the Kerguelen mantle plume. The temporal and spatial relationships between the Comei-Bunbury large igneous province and the Kerguelen mantle plume indicate that eastern Gondwana initially rifted at~147 Ma and that the Indian Plate fully separated from the Australian-Antarctic Plate before~124 Ma.